Biochemistry Questions and Answers – Coordinated Regulation of Glycogen Synthesis and Breakdown

This set of Biochemistry Questions and Answers for Aptitude test focuses on “Coordinated Regulation of Glycogen Synthesis and Breakdown”.

1. Glucagon and epinephrine stimulate glycogen breakdown to glucose 6-phosphate ________
a) Directly by binding to glycogen phosphorylase
b) Indirectly by first stimulating adenylate cyclase to make cAMP
c) Only in the liver
d) Only in muscle cells
View Answer

Answer: b
Explanation: The second messenger cAMP increases in concentration in response to stimulation by epinephrine in muscle or glucagon in liver.

2. Which compounds are responsible for the coordinated regulation of glucose and glycogen metabolism?
a) NADH
b) NAD+
c) Acetyl co-A
d) Fructose 2, 6-bisphosphate
View Answer

Answer: d
Explanation: The hormonal regulation of glycolysis and gluconeogenesis is mediated by fructose 2, 6-bisphosphate.

3. Glycogen synthase a is activated by ___________
a) Phosphorylation catalyzed by GSK3
b) Dephosphorylation catalyzed by GSK3
c) Phosphorylation catalyzed by pyruvate kinase
d) Phosphorylation catalyzed by pyruvate carboxylase
View Answer

Answer: a
Explanation: A protein kinase (PDK-1) that is activated when bound to PIP3 activates a second protein kinase (PKB) which phosphorylates glycogen synthase kinase 3 (GSK-3). The inactivation of GSK3 allows PP1 to dephosphorylate glycogen synthase converting it to its active form.
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4. Glucagon is released from ___________
a) Muscle
b) Pancreas
c) Kidneys
d) Epithelial tissues
View Answer

Answer: b
Explanation: Glucagon is released from pancreas and causes the liver to convert glycogen to glucose.

5. Glucose 6-phosphatase is present only in ___________
a) Liver
b) Muscle
c) Epithelial tissues
d) Kidneys
View Answer

Answer: a
Explanation: Glucose 6-phosphatase which hydrolyzes glucose 6-phosphate is present only in liver. Other tissues lack glucose 6-phosphatase.
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6. Which of the following enzymes is involved in the positive regulation of glycolysis/gluconeogenesis?
a) Hexokinase II
b) Hexokinase IV
c) PFK-2/FBPase-2
d) Pyruvate kinase
View Answer

Answer: c
Explanation: Increased expression of PFK-2/FBPase-2 regulates glycolysis/gluconeogenesis.

7. Which of the following enzymes is involved in fatty acid synthesis?
a) Hexokinase II
b) Hexokinase IV
c) PFK-2/FBPase-2
d) Pyruvate dehydrogenase
View Answer

Answer: d
Explanation: Hexokinase II and hexokinase IV involved in glycolysis.
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8. Which of the following is involved in triacylglycerol synthesis?
a) Hexokinase II
b) Acyl co-A glycerol transferases
c) PFK-2/FBPase-2
d) Pyruvate dehydrogenase
View Answer

Answer: b
Explanation: Hexokinase II involved in glycolysis, pyruvate dehydrogenase involved in fatty acid synthesis.

9. Which of the following is involved in pentose phosphate pathway?
a) Glucose 6-phosphate dehydrogenase
b) Acyl co-A glycerol transferases
c) PFK-2/FBPase-2
d) Pyruvate dehydrogenase
View Answer

Answer: a
Explanation: Acyl co-A glycerol transferases involved in triacylglycerol synthesis, pyruvate dehydrogenase involved in fatty acid synthesis.
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10. Which of the following enzyme’s gene expression is slowed by insulin?
a) Hexokinase II
b) Hexokinase IV
c) PEP carboxykinase
d) Pyruvate kinase
View Answer

Answer: c
Explanation: Insulin stimulates the transcription of the genes that encode hexokinase II, hexokinase IV and pyruvate kinase.

Sanfoundry Global Education & Learning Series – Biochemistry.

To practice all areas of Biochemistry for Aptitude test, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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